src/script/lua_api/l_env.cpp

/*
Minetest
Copyright (C) 2010-2013 kwolekr, Ryan Kwolek <kwolekr@minetest.net>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/


#include "mapgen.h"
#include "voxel.h"
#include "noise.h"
#include "mapblock.h"
#include "mapnode.h"
#include "map.h"
#include "content_sao.h"
#include "nodedef.h"
#include "voxelalgorithms.h"
#include "profiler.h"
#include "settings.h" // For g_settings
#include "emerge.h"
#include "dungeongen.h"
#include "cavegen.h"
#include "treegen.h"
#include "mg_biome.h"
#include "mg_ore.h"
#include "mg_decoration.h"
#include "mapgen_v5.h"
#include "util/directiontables.h"


FlagDesc flagdesc_mapgen_v5[] = {
	{NULL,         0}
};


MapgenV5::MapgenV5(int mapgenid, MapgenParams *params, EmergeManager *emerge)
	: Mapgen(mapgenid, params, emerge)
{
	this->m_emerge = emerge;
	this->bmgr     = emerge->biomemgr;

	// amount of elements to skip for the next index
	// for noise/height/biome maps (not vmanip)
	this->ystride = csize.X;
	this->zstride = csize.X * (csize.Y + 2);

	this->biomemap  = new u8[csize.X * csize.Z];
	this->heightmap = new s16[csize.X * csize.Z];
	this->heatmap   = NULL;
	this->humidmap  = NULL;

	MapgenV5Params *sp = (MapgenV5Params *)params->sparams;
	this->spflags      = sp->spflags;

	// Terrain noise
	noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
	noise_factor       = new Noise(&sp->np_factor,       seed, csize.X, csize.Z);
	noise_height       = new Noise(&sp->np_height,       seed, csize.X, csize.Z);

	// 3D terrain noise
	noise_cave1  = new Noise(&sp->np_cave1,  seed, csize.X, csize.Y + 2, csize.Z);
	noise_cave2  = new Noise(&sp->np_cave2,  seed, csize.X, csize.Y + 2, csize.Z);
	noise_ground = new Noise(&sp->np_ground, seed, csize.X, csize.Y + 2, csize.Z);

	// Biome noise
	noise_heat           = new Noise(&params->np_biome_heat,           seed, csize.X, csize.Z);
	noise_humidity       = new Noise(&params->np_biome_humidity,       seed, csize.X, csize.Z);
	noise_heat_blend     = new Noise(&params->np_biome_heat_blend,     seed, csize.X, csize.Z);
	noise_humidity_blend = new Noise(&params->np_biome_humidity_blend, seed, csize.X, csize.Z);

	//// Resolve nodes to be used
	INodeDefManager *ndef = emerge->ndef;

	c_stone                = ndef->getId("mapgen_stone");
	c_water_source         = ndef->getId("mapgen_water_source");
	c_lava_source          = ndef->getId("mapgen_lava_source");
	c_desert_stone         = ndef->getId("mapgen_desert_stone");
	c_ice                  = ndef->getId("mapgen_ice");
	c_sandstone            = ndef->getId("mapgen_sandstone");

	c_cobble               = ndef->getId("mapgen_cobble");
	c_stair_cobble         = ndef->getId("mapgen_stair_cobble");
	c_mossycobble          = ndef->getId("mapgen_mossycobble");
	c_sandstonebrick       = ndef->getId("mapgen_sandstonebrick");
	c_stair_sandstonebrick = ndef->getId("mapgen_stair_sandstonebrick");

	if (c_ice == CONTENT_IGNORE)
		c_ice = CONTENT_AIR;
	if (c_mossycobble == CONTENT_IGNORE)
		c_mossycobble = c_cobble;
	if (c_stair_cobble == CONTENT_IGNORE)
		c_stair_cobble = c_cobble;
	if (c_sandstonebrick == CONTENT_IGNORE)
		c_sandstonebrick = c_sandstone;
	if (c_stair_sandstonebrick == CONTENT_IGNORE)
		c_stair_sandstonebrick = c_sandstone;
}


MapgenV5::~MapgenV5()
{
	delete noise_filler_depth;
	delete noise_factor;
	delete noise_height;
	delete noise_cave1;
	delete noise_cave2;
	delete noise_ground;

	delete noise_heat;
	delete noise_humidity;
	delete noise_heat_blend;
	delete noise_humidity_blend;

	delete[] heightmap;
	delete[] biomemap;
}


MapgenV5Params::MapgenV5Params()
{
	spflags = 0;

	np_filler_depth = NoiseParams(0, 1,  v3f(150, 150, 150), 261,    4, 0.7,  2.0);
	np_factor       = NoiseParams(0, 1,  v3f(250, 250, 250), 920381, 3, 0.45, 2.0);
	np_height       = NoiseParams(0, 10, v3f(250, 250, 250), 84174,  4, 0.5,  2.0);
	np_cave1        = NoiseParams(0, 12, v3f(50,  50,  50),  52534,  4, 0.5,  2.0);
	np_cave2        = NoiseParams(0, 12, v3f(50,  50,  50),  10325,  4, 0.5,  2.0);
	np_ground       = NoiseParams(0, 40, v3f(80,  80,  80),  983240, 4, 0.55, 2.0, NOISE_FLAG_EASED);
}


//#define CAVE_NOISE_SCALE 12.0
//#define CAVE_NOISE_THRESHOLD (1.5/CAVE_NOISE_SCALE) = 0.125


void MapgenV5Params::readParams(const Settings *settings)
{
	settings->getFlagStrNoEx("mgv5_spflags", spflags, flagdesc_mapgen_v5);

	settings->getNoiseParams("mgv5_np_filler_depth", np_filler_depth);
	settings->getNoiseParams("mgv5_np_factor",       np_factor);
	settings->getNoiseParams("mgv5_np_height",       np_height);
	settings->getNoiseParams("mgv5_np_cave1",        np_cave1);
	settings->getNoiseParams("mgv5_np_cave2",        np_cave2);
	settings->getNoiseParams("mgv5_np_ground",       np_ground);
}


void MapgenV5Params::writeParams(Settings *settings) const
{
	settings->setFlagStr("mgv5_spflags", spflags, flagdesc_mapgen_v5, (u32)-1);

	settings->setNoiseParams("mgv5_np_filler_depth", np_filler_depth);
	settings->setNoiseParams("mgv5_np_factor",       np_factor);
	settings->setNoiseParams("mgv5_np_height",       np_height);
	settings->setNoiseParams("mgv5_np_cave1",        np_cave1);
	settings->setNoiseParams("mgv5_np_cave2",        np_cave2);
	settings->setNoiseParams("mgv5_np_ground",       np_ground);
}


int MapgenV5::getGroundLevelAtPoint(v2s16 p)
{
	//TimeTaker t("getGroundLevelAtPoint", NULL, PRECISION_MICRO);

	float f = 0.55 + NoisePerlin2D(&noise_factor->np, p.X, p.Y, seed);
	if (f < 0.01)
		f = 0.01;
	else if (f >= 1.0)
		f *= 1.6;
	float h = NoisePerlin2D(&noise_height->np, p.X, p.Y, seed);

	s16 search_top = water_level + 15;
	s16 search_base = water_level;

	s16 level = -31000;
	for (s16 y = search_top; y >= search_base; y--) {
		float n_ground = NoisePerlin3D(&noise_ground->np, p.X, y, p.Y, seed);
		if (n_ground * f > y - h) {
			if (y >= search_top - 7)
				break;
			else
				level = y;
				break;
		}
	}

	//printf("getGroundLevelAtPoint: %dus\n", t.stop());
	return level;
}


void MapgenV5::makeChunk(BlockMakeData *data)
{
	// Pre-conditions
	assert(data->vmanip);
	assert(data->nodedef);
	assert(data->blockpos_requested.X >= data->blockpos_min.X &&
		data->blockpos_requested.Y >= data->blockpos_min.Y &&
		data->blockpos_requested.Z >= data->blockpos_min.Z);
	assert(data->blockpos_requested.X <= data->blockpos_max.X &&
		data->blockpos_requested.Y <= data->blockpos_max.Y &&
		data->blockpos_requested.Z <= data->blockpos_max.Z);

	generating = true;
	vm   = data->vmanip;
	ndef = data->nodedef;
	//TimeTaker t("makeChunk");

	v3s16 blockpos_min = data->blockpos_min;
	v3s16 blockpos_max = data->blockpos_max;
	node_min = blockpos_min * MAP_BLOCKSIZE;
	node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
	full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
	full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);

	// Create a block-specific seed
	blockseed = getBlockSeed2(full_node_min, seed);

	// Make some noise
	calculateNoise();

	// Generate base terrain
	s16 stone_surface_max_y = generateBaseTerrain();

	// Create heightmap
	updateHeightmap(node_min, node_max);

	// Create biomemap at heightmap surface
	bmgr->calcBiomes(csize.X, csize.Z, noise_heat->result,
		noise_humidity->result, heightmap, biomemap);

	// Actually place the biome-specific nodes
	MgStoneType stone_type = generateBiomes(noise_heat->result, noise_humidity->result);

	// Generate caves
	if ((flags & MG_CAVES) && (stone_surface_max_y >= node_min.Y))
		generateCaves(stone_surface_max_y);

	// Generate dungeons and desert temples
	if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
		DungeonParams dp;

		dp.np_rarity  = nparams_dungeon_rarity;
		dp.np_density = nparams_dungeon_density;
		dp.np_wetness = nparams_dungeon_wetness;
		dp.c_water    = c_water_source;
		if (stone_type == STONE) {
			dp.c_cobble = c_cobble;
			dp.c_moss   = c_mossycobble;
			dp.c_stair  = c_stair_cobble;

			dp.diagonal_dirs = false;
			dp.mossratio     = 3.0;
			dp.holesize      = v3s16(1, 2, 1);
			dp.roomsize      = v3s16(0, 0, 0);
			dp.notifytype    = GENNOTIFY_DUNGEON;
		} else if (stone_type == DESERT_STONE) {
			dp.c_cobble = c_desert_stone;
			dp.c_moss   = c_desert_stone;
			dp.c_stair  = c_desert_stone;

			dp.diagonal_dirs = true;
			dp.mossratio     = 0.0;
			dp.holesize      = v3s16(2, 3, 2);
			dp.roomsize      = v3s16(2, 5, 2);
			dp.notifytype    = GENNOTIFY_TEMPLE;
		} else if (stone_type == SANDSTONE) {
			dp.c_cobble = c_sandstonebrick;
			dp.c_moss   = c_sandstonebrick;
			dp.c_stair  = c_sandstonebrick;

			dp.diagonal_dirs = false;
			dp.mossratio     = 0.0;
			dp.holesize      = v3s16(2, 2, 2);
			dp.roomsize      = v3s16(2, 0, 2);
			dp.notifytype    = GENNOTIFY_DUNGEON;
		}

		DungeonGen dgen(this, &dp);
		dgen.generate(blockseed, full_node_min, full_node_max);
	}

	// Generate the registered decorations
	m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);

	// Generate the registered ores
	m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);

	// Sprinkle some dust on top after everything else was generated
	dustTopNodes();

	//printf("makeChunk: %dms\n", t.stop());

	// Add top and bottom side of water to transforming_liquid queue
	updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);

	// Calculate lighting
	if (flags & MG_LIGHT) {
		calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
			full_node_min, full_node_max);
	}

	this->generating = false;
}


void MapgenV5::calculateNoise()
{
	//TimeTaker t("calculateNoise", NULL, PRECISION_MICRO);
	int x = node_min.X;
	int y = node_min.Y - 1;
	int z = node_min.Z;

	noise_factor->perlinMap2D(x, z);
	noise_height->perlinMap2D(x, z);
	noise_ground->perlinMap3D(x, y, z);

	if (flags & MG_CAVES) {
		noise_cave1->perlinMap3D(x, y, z);
		noise_cave2->perlinMap3D(x, y, z);
	}

	noise_filler_depth->perlinMap2D(x, z);
	noise_heat->perlinMap2D(x, z);
	noise_humidity->perlinMap2D(x, z);
	noise_heat_blend->perlinMap2D(x, z);
	noise_humidity_blend->perlinMap2D(x, z);

	for (s32 i = 0; i < csize.X * csize.Z; i++) {
		noise_heat->result[i] += noise_heat_blend->result[i];
		noise_humidity->result[i] += noise_humidity_blend->result[i];
	}

	heatmap = noise_heat->result;
	humidmap = noise_humidity->result;
	//printf("calculateNoise: %dus\n", t.stop());
}


//bool is_cave(u32 index) {
//	double d1 = contour(noise_cave1->result[index]);
//	double d2 = contour(noise_cave2->result[index]);
//	return d1*d2 > CAVE_NOISE_THRESHOLD;
//}

//bool val_is_ground(v3s16 p, u32 index, u32 index2d) {
//	double f = 0.55 + noise_factor->result[index2d];
//	if(f < 0.01)
//		f = 0.01;
//	else if(f >= 1.0)
//		f *= 1.6;
//	double h = WATER_LEVEL + 10 * noise_height->result[index2d];
//	return (noise_ground->result[index] * f > (double)p.Y - h);
//}


int MapgenV5::generateBaseTerrain()
{
	u32 index = 0;
	u32 index2d = 0;
	int stone_surface_max_y = -MAP_GENERATION_LIMIT;

	for (s16 z=node_min.Z; z<=node_max.Z; z++) {
		for (s16 y=node_min.Y - 1; y<=node_max.Y + 1; y++) {
			u32 i = vm->m_area.index(node_min.X, y, z);
			for (s16 x=node_min.X; x<=node_max.X; x++, i++, index++, index2d++) {
				if (vm->m_data[i].getContent() != CONTENT_IGNORE)
					continue;

				float f = 0.55 + noise_factor->result[index2d];
				if (f < 0.01)
					f = 0.01;
				else if (f >= 1.0)
					f *= 1.6;
				float h = noise_height->result[index2d];

				if (noise_ground->result[index] * f < y - h) {
					if (y <= water_level)
						vm->m_data[i] = MapNode(c_water_source);
					else
						vm->m_data[i] = MapNode(CONTENT_AIR);
				} else {
					vm->m_data[i] = MapNode(c_stone);
					if (y > stone_surface_max_y)
						stone_surface_max_y = y;
				}
			}
			index2d -= ystride;
		}
		index2d += ystride;
	}

	return stone_surface_max_y;
}


MgStoneType MapgenV5::generateBiomes(float *heat_map, float *humidity_map)
{
	v3s16 em = vm->m_area.getExtent();
	u32 index = 0;
	MgStoneType stone_type = STONE;

	for (s16 z = node_min.Z; z <= node_max.Z; z++)
	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
		Biome *biome = NULL;
		u16 depth_top = 0;
		u16 base_filler = 0;
		u16 depth_water_top = 0;
		u32 vi = vm->m_area.index(x, node_max.Y, z);

		// Check node at base of mapchunk above, either a node of a previously
		// generated mapchunk or if not, a node of overgenerated base terrain.
		content_t c_above = vm->m_data[vi + em.X].getContent();
		bool air_above = c_above == CONTENT_AIR;
		bool water_above = c_above == c_water_source;

		// If there is air or water above enable top/filler placement, otherwise force
		// nplaced to stone level by setting a number exceeding any possible filler depth.
		u16 nplaced = (air_above || water_above) ? 0 : (u16)-1;

		for (s16 y = node_max.Y; y >= node_min.Y; y--) {
			content_t c = vm->m_data[vi].getContent();

			// Biome is recalculated each time an upper surface is detected while
			// working down a column. The selected biome then remains in effect for
			// all nodes below until the next surface and biome recalculation.
			// Biome is recalculated:
			// 1. At the surface of stone below air or water.
			// 2. At the surface of water below air.
			// 3. When stone or water is detected but biome has not yet been calculated.
			if ((c == c_stone && (air_above || water_above || !biome)) ||
					(c == c_water_source && (air_above || !biome))) {
				biome = bmgr->getBiome(heat_map[index], humidity_map[index], y);
				depth_top = biome->depth_top;
				base_filler = MYMAX(depth_top + biome->depth_filler
						+ noise_filler_depth->result[index], 0);
				depth_water_top = biome->depth_water_top;

				// Detect stone type for dungeons during every biome calculation.
				// This is more efficient than detecting per-node and will not
				// miss any desert stone or sandstone biomes.
				if (biome->c_stone == c_desert_stone)
					stone_type = DESERT_STONE;
				else if (biome->c_stone == c_sandstone)
					stone_type = SANDSTONE;
			}

			if (c == c_stone) {
				content_t c_below = vm->m_data[vi - em.X].getContent();

				// If the node below isn't solid, make this node stone, so that
				// any top/filler nodes above are structurally supported.
				// This is done by aborting the cycle of top/filler placement
				// immediately by forcing nplaced to stone level.
				if (c_below == CONTENT_AIR || c_below == c_water_source)
					nplaced = (u16)-1;

				if (nplaced < depth_top) {
					vm->m_data[vi] = MapNode(biome->c_top);
					nplaced++;
				} else if (nplaced < base_filler) {
					vm->m_data[vi] = MapNode(biome->c_filler);
					nplaced++;
				} else {
					vm->m_data[vi] = MapNode(biome->c_stone);
				}

				air_above = false;
				water_above = false;
			} else if (c == c_water_source) {
				vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top)) ?
						biome->c_water_top : biome->c_water);
				nplaced = 0;  // Enable top/filler placement for next surface
				air_above = false;
				water_above = true;
			} else if (c == CONTENT_AIR) {
				nplaced = 0;  // Enable top/filler placement for next surface
				air_above = true;
				water_above = false;
			} else {  // Possible various nodes overgenerated from neighbouring mapchunks
				nplaced = (u16)-1;  // Disable top/filler placement
				air_above = false;
				water_above = false;
			}

			vm->m_area.add_y(em, vi, -1);
		}
	}

	return stone_type;
}


void MapgenV5::generateCaves(int max_stone_y)
{
	if (max_stone_y >= node_min.Y) {
		u32 index = 0;

		for (s16 z = node_min.Z; z <= node_max.Z; z++)
		for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
			u32 i = vm->m_area.index(node_min.X, y, z);
			for (s16 x = node_min.X; x <= node_max.X; x++, i++, index++) {
				float d1 = contour(noise_cave1->result[index]);
				float d2 = contour(noise_cave2->result[index]);
				if (d1*d2 > 0.125) {
					content_t c = vm->m_data[i].getContent();
					if (!ndef->get(c).is_ground_content || c == CONTENT_AIR)
						continue;

					vm->m_data[i] = MapNode(CONTENT_AIR);
				}
			}
		}
	}

	if (node_max.Y > LARGE_CAVE_DEPTH)
		return;

	PseudoRandom ps(blockseed + 21343);
	u32 bruises_count = (ps.range(1, 4) == 1) ? ps.range(1, 2) : 0;
	for (u32 i = 0; i < bruises_count; i++) {
		CaveV5 cave(this, &ps);
		cave.makeCave(node_min, node_max, max_stone_y);
	}
}


void MapgenV5::dustTopNodes()
{
	if (node_max.Y < water_level)
		return;

	v3s16 em = vm->m_area.getExtent();
	u32 index = 0;

	for (s16 z = node_min.Z; z <= node_max.Z; z++)
	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);

		if (biome->c_dust == CONTENT_IGNORE)
			continue;

		u32 vi = vm->m_area.index(x, full_node_max.Y, z);
		content_t c_full_max = vm->m_data[vi].getContent();
		s16 y_start;

		if (c_full_max == CONTENT_AIR) {
			y_start = full_node_max.Y - 1;
		} else if (c_full_max == CONTENT_IGNORE) {
			vi = vm->m_area.index(x, node_max.Y + 1, z);
			content_t c_max = vm->m_data[vi].getContent();

			if (c_max == CONTENT_AIR)
				y_start = node_max.Y;
			else
				continue;
		} else {
			continue;
		}

		vi = vm->m_area.index(x, y_start, z);
		for (s16 y = y_start; y >= node_min.Y - 1; y--) {
			if (vm->m_data[vi].getContent() != CONTENT_AIR)
				break;

			vm->m_area.add_y(em, vi, -1);
		}

		content_t c = vm->m_data[vi].getContent();
		if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
			vm->m_area.add_y(em, vi, 1);
			vm->m_data[vi] = MapNode(biome->c_dust);
		}
	}
}
	Commit message (Expand)	Author	Age
*	Emergeblocks: Fix occasional crash	Rogier	2016-10-16
*	Player/LocalPlayer/RemotePlayer inheritance cleanup (part 1 on X)	Loic Blot	2016-10-08
*	Change internal type for seeds to s32	kwolekr	2016-06-04
*	Pathfinder: Fix style	est31	2016-05-01
*	Add consistent monotonic day counter - get_day_count()	Auke Kok	2016-03-09
*	Add minetest.register_lbm() to run code on block load only	est31	2016-03-07
*	Add '/clearobjects quick'	Kahrl	2016-02-11
*	Add callback parameter for core.emerge_area()	kwolekr	2015-11-02
*	SAPI: Move core.get_us_time() to Util module	kwolekr	2015-10-26
*	SAPI: Mark all Lua API functions requiring envlock	kwolekr	2015-10-25
*	Add /emergeblocks command and core.emerge_area() Lua API	kwolekr	2015-09-23
*	Push error handler afresh each time lua_pcall is used	Kahrl	2015-08-27
*	SEnv: Remove static_exists from ActiveObjects in deleted blocks	kwolekr	2015-08-16
*	SAPI: Track last executed mod and include in error messages	kwolekr	2015-08-12
*	Improve Script CPP API diagnostics	kwolekr	2015-08-05
*	Add return list of individual counts to find_node_in_area	TeTpaAka	2015-06-13
*	Add core.find_nodes_with_meta() script API	kwolekr	2015-05-05
*	Use std::vector instead of std::set for Environment::getObjectsInsideRadius	Loic Blot	2015-04-16
*	For usages of assert() that are meant to persist in Release builds (when NDEB...	Craig Robbins	2015-03-07
*	Change find_surface_nodes_in_area to find_nodes_in_area_under_air	Craig Robbins	2015-02-27
*	Add find_surface_nodes_in_area LUA call which permit to only get the nodes wh...	Loic Blot	2015-02-27
*	SAO work: ActiveObject types & SAO cleanup * Replace u8 types with ActiveObje...	Loic Blot	2015-02-17
*	Performance Improvement: Use a cache which caches result for getFacePositions.	Loic Blot	2015-02-16
*	Add ability to delete MapBlocks from map	kwolekr	2015-01-15
*	LuaVoxelManip: Remove blank allocator	kwolekr	2014-12-29
*	LuaVoxelManip: Add option to allocate blank data	kwolekr	2014-12-27
*	Add support for NoiseParams in minetest.get_perlin() and add docs on NoisePar...	kwolekr	2014-12-12
*	Add flags and lacunarity as new noise parameters	kwolekr	2014-12-07
*	Remove most exceptions from getNode() (and variants)	Craig Robbins	2014-11-14
*	Fix object reference pushing functions when called from coroutines	ShadowNinja	2014-10-07
*	Add LuaVoxelManip methods: get_node_at() and set_node_at()	kwolekr	2014-09-01
*	Fix seg fault if popping from empty stack (L-system trees)	Craig Robbins	2014-08-23
*	Mod profiling support	sapier	2014-08-19
*	Use "core" namespace internally	ShadowNinja	2014-05-08
*	Remove liquid_finite and weather	proller	2014-04-18
*	Pass pointed_thing to on_punch and minetest.register_on_punchnode callbacks	ShadowNinja	2014-01-23
*	Add forceloading	Novatux	2014-01-11
*	Make line_of_sight return blocking node position	stujones11	2013-12-12
*	Optimize table creation	ShadowNinja	2013-11-30
*	Add minetest.swap_node	Novatux	2013-11-30
*	Fix line_of_sight (AGAIN)	sapier	2013-11-25
*	Pass a errfunc to lua_pcall to get a traceback	ShadowNinja	2013-11-15
*	Weather: Clean up getHeat/getHumidity somewhat	kwolekr	2013-09-16
*	Add minetest.get_gametime() API function, that returns the number of seconds ...	Novatux	2013-09-08
*	Omnicleanup: header cleanup, add ModApiUtil shared between game and mainmenu	Kahrl	2013-08-14
*	Better snow fall, finite liquid transform, leveled nodes api	proller	2013-07-28
*	Weather support	proller	2013-07-27
*	LuaVoxelManip: Fix minor bug with set_lighting, remove coordinate params for ...	kwolekr	2013-06-29
*	Apply various fixes to several things	kwolekr	2013-06-27
*	LuaVoxelManip: Separate VoxelManip data get/set from emerging/blitting data b...	kwolekr	2013-06-27